When I was picking which college to apply to at Cambridge, I was initially set on only applying to a college with in-person interviews for similar reasons as you. I ended up scratching that idea and picking Downing and found the online-ness to be acceptable, though naturally it was still very stressful. I had an in-person interview at another uni, and I would say I actually found myself to be slightly more comfortable in the online one, where I was in my own home rather than some unfamiliar room (I'll admit that the format of the in-person one was slightly different, which may have affected how I felt). I imagine that, regardless of where you do your interview, it will be uncomfortable, since the pressure on you is at its peak. The differences are perhaps especially less pronounced for an interview for a course like engineering, where the questions are more focused on problems and maths and so it is less personal. My advice would therefore be to just pick the college you like best and completely ignore the interview type. Good luck!